Sheet transfer device



Feb. 27, 1962 w. Q. PENDLEY 3,022,997

SHEET TRANSFER DEVICE Filed Nov. 24, 1958 m Z1 .5 mi

66 mg i 94 76 90 o 5 g 33/ i /04 92 g s; 1 7 5 INVENTOR WILL/AM Q.PENDLE) BY faM ATTORNEY United States This invention relates to a sheettransfer device and especially to a pickup and transfer apparatus foruse in handling sheets and signatures and particularly in the printingtrade in collating parts of a finished group of sheets.

This is a continuation-in-part of my co-pending application SerialNumber 625,140, filed November 29, 1956. As set forth in detail in thisco-pending application, sheets of printed paper representing diiferentparts of a finished book are collated or collected in sequence, inorder, by arranging the different sheets in individual stacks on acommon base which is moved; and during movement of the common base,sheets are picked up in proper sequence and transferred to a centralpoint where they are deposited in proper order. The particular structureused for this is a sheet pickup frame at each individual station whichmoves upwardly and downwardly in response to a track against which it isguided. On this frame are suction cups that engage the topsheet andadhere to it while suction is applied through them from avacuum-producing means.

The present invention is an improvement on the sheet pickup stationlifting frame apparatus by providing such things as an improved supportfor the sheets or signatures which assures substantially even, level topsheets even Where one side has accumulated and bunched due to heaviermargins. A signature is a folded o-r assem bled group of individualsheets about a common edge or margin and this margin inherently isthicker than the thickness of the other edge of sheets. For this reason,a stack of signature sheets will lie higher on one side at the marginedge than on the other side, thereby presenting a top surface which isslanting from the margin side to the other edge. It is difficult for asheet pickup device to engage the top sheet or signature evenly when thesheet or signature itself lies in a slanting plane to the horizontal.The present improvement provides a base for the stack of sheets orsignatures which compensates for the unevenness or bunch or build-up ofthe stack at the margins and continuously and automatically compensatesfor this as the sheets are removed, since the accumulated build-updiminishes from the top as the sheets are removed.

In conjunction and cooperation with the compensating rack base of thisdevice, the sheet engaging and transfer frame has been modified topresent self-adjusting suction cups and also an adjustment which may bemade manually to vary the contact distance between the frame and the topof the sheet stack thereby varying the contact of the suction cups withthe top sheet.

A primary object of this invention is to present a sheet transfer framedevice which has self-adjusting suction cups to fit the incline of thetop sheet.

Another object is to provide on the transfer device,

in addition to the self-adjusting suction cups, a control device forvarying the contact of the apparatus with the top sheet to permit thecups to engage freely. An additional object is to provide in conjunctionwith the transfer frame a base having a means thereon for compensatingfor stack build-up at the marginal edges of the sheets and as anadditional feature a provision for compensating during the removal ofthe sheets.

Other and further objects and advantages of my invention will beapparent from the following description taken in conjunction with theaccompanying drawings, wherein:

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FIG. 1 is a perspective view of the entire sheet handling device withthe movable base of the overall machine broken away.

FIG. 2 is a front side elevation view of the individual stack supportbase of the device shown in FIG. 1.

FIG. 3 is a perspective view of the compensating stack base of thedevice in FIG. 1.

FIG. 4 is a back side elevation view of the bottom portion of the stacktransfer device in FIG. 1 showing an adjustment detail.

FIG. 5 is a cross-section view through one of the compensation plungerson the base of the device in FIG. 1.

The overall device itself is designated and presented as a singlestation 10 and is positioned as part of a composite collating orsignature gathering machine having a common base 12 on which allidentical stations 10 are located, each being the position for a stackof different sheets. Since the details of the overall collating machineare not herein involved, base 12 and the remainder of the machine havebeen broken away. Rigidly fastened on base 12 by any suitable means is apair of upright support, slide rod members 14 on which the sheettransfer device moves in sliding engagement upwardly and downwardlythereon by means of a pair of tubular slide members 16, 18 connected byrigid cross-bars 20, 22 and having fixed to member 22 a track guidesupport arm 24 with a track roller wheel 26 thereon. Member 2% is ahollow conduit. Normally the entire device is guided by engagement ofwheel 26 with a guide track 27 to move the device upwardly anddownwardly in sliding move ment on rods 14. As the members 16, 18 slidedownwardly the entire device moves toward and eventually against thestack of sheets therebelow.

Protruding from and rigidly fixed on bottom member 20 is a pair ofextension arms 23, 30 connected together and supporting a frame member32 therebelow having a pair of suction cup support levers 34 mountedthereon. Each lever 34 is a straight flat bar with a journal end portion36 loosely mounted on and for rotation about the frame member 32 so thatthe levers will move independently of each other on the member 32 andeach lever has mounted thereon a suction cup, hollow conduit sup- 1 port38 having a suction cup 40 sliding for limited move merit therein on ahollow rod 42. Suction cups 40 are in suction communication with theconduit 38 to have a vacuum produced therein in response to a vacuumproduced through the line 38. Each conduit 38 is connected by a flexiblehose 44 to the conduit 26 providing a central suction supply throughwhich both air and suction are applied. Rigidly mounted on therespective levers 34 in front of each suction cup 40 is an air nozzle 46connected by a flexible hose 48 to the central line 20. Through theoperation of a valve timing device, not forming a part of this presentinvention and being shown in my co-pending application identifiedpreviously, the suction cups 40 are'supplied with the suction, and thenozzles 46 are suppliedwith air to blow against the stacked sheets andloosen them slightly to separate them for pickup by the cups 40.

Attached on each lever 34 is a respective upstanding post 50 with anadjustment tab 52 screwed thereon and resting on top of and against thearm 28 as each lever 34 hangs on its journal 36 to limit the downwardtravel of each lever 34 thereby maintaining the levers 34 in a slightlyraised position. Since the engagement of tabs 52 against a respectivearm 28 is a loose abutment by gravity, pressure against the levers 34,as when hitting against the top sheet, will cause the levers 34 toraise, each independently of the others.

Depending from and attached to arm 30 is an adjustment frame 54 (FIG. 4in particular) which determines the point at which the suction cups 4ahit and consisting of a pair of spaced blocks 56 attached to the arm 30supporting a respective member 58 each having a journal block 69 at theend thereof in which is journaled a shaft member 62. A pair of pivotblocks 64 on shaft 62 are connected by upper and lower arms 66,68.Rotation of blocks 64 on shaft 62 is prevented by a latch member 70consisting of a cup-shaped retainer 72 fitting over one or the other ofarms 66, 68 and fixed to a pin 74 sliding in a collar 76 attached onmember 30. Accordingly, arm 66 is spaced further away'from shaft 62 thanis arm 68 so that the distance of abutment from either one of the arms66, 68 or shaft 62 may be adjusted by rotating the entire block assembly64 on shaft 62 to one of three positions: arm 66 down; arm 68 down; orarms 66, 68 and shaft 62 in a horizontal line. This provides anadjustment of the point at which the device it) reaches its maximumtravel downwardly and strikes the stack top, thereby lending anadjustment to the striking of the cups 40 against the stack top. Byplacing the short side 68 down, the cups 40 will lower less than if themiddle shaft 62 were down, while having the long side 66 down willreduce the travel even more than with the side 68.

Cooperating with and co-acting with the device is the stack holding andpositioning rack 80 consisting of a box-like base 82 of bent metal orthe like attached to the moving base 12 of the overall machine beneaththe device 18. As apparent in FIG. 2, the arrangement of this rack 80maintains a stack of signature sheets 84 with the top sheetsubstantially level from side to side even though the outside marginaledges of the sheets 84 are thicker than the inside edges.

Sheets 84, which may be signature sheets folded from larger sheets, arestacked on the top 86 of base 82 and positioned in place by guidemembers consisting of front vertical guide bars 88 adjustably fastenedby screws 90 on a front block 92, intermediate side positioning,vertical strips 24 having inturned bottom edges with elongatedadjustment slots 96 receiving attachment screws 98; in base 82, and rearpositioning strips 100 with bent bottom ends adjustably screwed to base82. Removably positioned on base 82 about the rear strips 100 arestacked E-shaped adjustment platforms 102 of selected thickness. Theremay be as many or as few platforms 102 as needed to balance out theinitial cumulative bunch or build-up of the front edge of sheets 84.Located at the front on base 82 are automatic compensating plungers 104mounted in tubes 106 fastened on base 82 and confining inside the tubes106 a respective spring 108.

Initially, in loading all stations adjacent devices 10, the sheet stackguides 88, 94, 100 are adjusted by sight about the stack of sheet andplatforms 102 are selected according to thickness and number tocompensate for the cumulative bunch or build-up at the outer marginaledges (FIG. 2). By trial run, the suction cup 40 downward engagement andtravel are adjusted against the top of the stack of sheets 84 to givethe best engagement and pickup. Whenever more or less positiveengagement against the top sheet 84 is needed, the frame arrangementblocks 6-4 are adjusted by lifting pin 74 with retainer 72 and turningblocks 64 about shaft 62 to the proper place. As stack 64 diminishes insize by the sheets being removed, the marginal bunch or build-up becomesless and less and gradually, if it were not for the plungers 164, the

, platforms 102 would cause a cumulative bunchon the opposite side.However, as the weight of stack 64 diminishes, plungers 104 aretendingto produce more and more effect on the stack front marginal edgeand thereby compensate for the loss in build-up. at thetop by pushingupwardly from the bottom.

With this arrangement, once a stack 64 of sheets has been placed in therack 80 in proper alignment and the initial front bunch compensated forby dropping the front from the rear platforms 102, the machine may be.operated to bring the device 10 in engagement with the stack top 64 andif necessary the stack engagement is adjusted at the frame '54. Then themachine may be run without regard'to the change in front build-upresulting from sheet 64 removal since the plungers 194 compensate forthat. Any other curvature, slant or unevenness at the top of the sheets64 is compensated for and the effect minimized by the adjustment of theframe 54 to give more or less positive engagement between the cups 40and the sheet tops 64 and in addition each lever 34 is independent ofany other so that even though there is not a straight line or planebetween respective cups 40 each cup will nevertheless make suitablecontact at its particularposition.

While I have shown and described a particular embodiment of my inventionin detail herein and point out certain advantages thereof, this is notto be construed as the only advantages or as the only form of myinvention since various alterations, substitutions, changes,eliminations, variations, and modifications may be made in the deviceshown without departing from the scope of my invention defined in theappended claims.

I claim:

1. In a sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is guided and moved on a moving machine baseand a control member moves the station in response to a machine controlwhich also provides suction for engaging a sheet, station support meanson said machine movable thereon to transfer a sheet, suction supportsmounted for arcuate movement on said station support means, suctionmeans on said suction supports having spaced suction surfacesindependently operable against the top of the stack to adjust across anyunevenness thereof, and adjustable means on said station for adjustingthe point of contact with said stack to bring said suction means evenlyinto engagement with said stack top.

2. In a sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is guided and moved on a moving machine baseand a control member moves the station in response to machine controlwhich also provides a timed vacuum to said station, a substantially fiatstack positioning surface adjacent said transfer station for holding astack of sheets to be transferred therefrom, means on said surface forcausing said stack to be substantially level at the top thereof evenwhen said sheets are thicker on one side, said means on said surfacecompensating for the loss in build-up of the thicker side as said stackdiminishes from sheets being removed therefrom to maintain the top ofsaid stack substantially level from a full stack to a partly emptystack.

3. The device of claim 2 wherein there is an adjustable stack contactstop member for positioning said station against said stack.

4. in a sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is guided and moved on a moving machine baseand a control member moves the station'in response to machine controlwhich also provides a timed vacuum and an independently timed airpressure to said station, station support means extending from saidmachine and base and being supported for movement thereon relativethereto as said station moves on said base to transfer sheetsfrom thestack thereon, suction supports mounted for arcuate movement on saidstation support means, suction cups mounted for independent movement oneach said suction supports and being supported thereon above said stackto engage the top sheet thereof, each of said suctioncups being freelymovable by contact with the stack top independently of the other so asto compensate for any unevenness of the stack top, and said suctionsupports moving arcuately and independently against said stack to adjustfor any unevenness across said stack either longitudinally ortransversely thereof' 5. In a sheet transfer station for moving sheetsfrom a stack of sheets wherein the sheet station is guided and moved ona moving machine base and a control member moves the station in responseto machine control which also provides a timed vacuum and anindependently timed air pressure to said station, a substantially fiatstack positioning surface adjacent said transfer station for holding astack of sheets to be transferred therefrom, means on said surface forcompensating the accumulated buildup of one side of said stack to causesaid stack to be substantially level at the top thereof, and springloaded plunger means on said surface for compensating for the loss inbuild-up as said stack diminishes from sheets being removed therefrom tomaintain the top of said stack substantially level from a full stack toa partly empty stack, said plungers normally being depressed when saidstack is fuller and gradually pushing the stack as sheets are removed.

6. In a sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is guided and moved on a moving machine baseand a control member moves the station in response to machine controlwhich also provides a timed vacuum and an independently timed airpressure to said station, station support means extending from saidmachine and base and being supported for movement thereon relativethereto as said station moves on said base to transfer sheets from thestack thereon, suction supports mounted for arcuate movement on saidstation support means, suction cups mounted for independent movement onsaid suction supports and being supported thereon above said stack toengage the top sheet thereof, each of said suction cups being freelymovable by contact with the stack top independently of the other so asto compensate for any unevenness of the stack top, and adjustable stackstop means on said station adjustable to determine the contact of theentire station with the stack top whereby said suction cups yieldablyengage the stack top to make suction engagement with the top sheetthereof, and said suction supports moving arcuately and independentlyagainst said stack to adjust for any unevenness across said stack bothtransversely and longitudinally thereof.

7. In a sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is guided and moved on a moving machine baseand a control member moves the station in response to machine controlwhich also provides a timed vacuum and an independently timed airpressure to said station, a substantially fiat stack positioning surfaceadjacent said transfer station for holding a stack of sheets to betransferred therefrom, a plurality of selectively removable platformlifts on said surface for compensating the accumulated build-up of oneside of said stack to cause said stack to be substantially level at thetop thereof, and other compensating means on said surface forcompensating the other side of said stack for the loss in build-up asthe initially lifted side of said stack diminishes from sheets beingremoved therefrom to maintain the top of said stack substantially levelfrom a full stack to a partly empty stack.

8. In a sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is'guided and moved on a moving machine baseand a control member moves the station in response to machine controlwhich also provides a timed vacuum and an independently timed airpressure to said station, station support means extending from saidmachine and base and being supported for movement thereon relativethereto as said station moves on said base to transfer sheets from thestack thereon, a plurality of suction cups pivotally mounted forindependent movement on said station sup port means and being supportedthereon above saidstack to engage the top sheet thereof, each of saidsuction cups being retained over said stack from downward movement andfreely movable'by contact with .the stack top independently of the otherso as to compensate for any unevenness of thelstack top, and anadjustable stack stop frame on said station having a plurality ofcontact members selectively adjustable to determine the contact of 6 theentire station with the stack top whereby said suction cups yieldablyengage the stack top to make suction engagement with the top sheetthereof.

tially flat stack position ng surface adjacent said transfer station forholding a stack of sheets to be transferred therefrom, adjustableplatform means on said surface for initially adjustably lifting one sideof said stack for compensating the accumulated build-up at one side ofsaid stack from any excess thickness of one side of said sheet comparedto any other side to cause said stack to be substantially level at thetop thereof, a plurality of spring loaded plungers on said surfacecompensating for the loss in build-up as said stack diminishes fromsheets being removed therefrom to maintain the top of said stacksubstantially level from a full stack to a partly empty stack.

10. In a sheet transfer station for moving sheets from a stack of sheetswherein guide members are provided on a machine base and a controlmember moves the station in response to machine control which alsoprovides a timed vacuum and an independent air pressure to saidstations, station support members extending from said guide members,means supporting said support members for transfer movement on said baseguide members, spaced suction cup levers mounted for pivotal movement onsaid station support members, each of said levers having a positioningmeans thereon normally yieldably positioning each thereof on saidstation supports, each of said levers being freely movable on its pivotupwardly and being limited in downward movement by said positioningmeans whereby contact of said lever with a stack will push said leverupwardly, each of said levers having a suction cup thereon in closedcommunication with a suction line attached thereto, a stack limitingmeans mounted on said station comprising a plurality of stack engagementmembers mounted on said support means each being positionable to adifferent stack engagement level, an adjustable means on said stacklimiting means normally retaining one of said stack engagement membersin set position, whereby said cups are yieldable and said station may beadjusted as to contact with said stack.

' 11. In a sheet transfer station for moving sheets from a stack ofsheets wherein guide members are provided on a machine base and acontrol member moves the station in response to machine control whichalso provides a timed vacuum and an independent air pressure to saidstation, support means supporting said station movably for transfermovement on said base guide members, a plurality .of movable suctioncups on said support movable both with and in limited relative distanceon said support means, conduit means on said support means connectingsaid suction cups to said timed vacuum of said machine, a stack limitingmeansmounte'd on said station comprising a pinrality of stack engagementmembers mounted on said sup- .port means each being positionable to adifferent stack engagement position, an adjustable means on said'stacklimiting means normally retaining one of said stack engagement membersin set position, a sheet stack base mounted on said machine below saidstation transfer device and having a raised base bottom with raisedstack positioning members adjustably mounted on said base to bepre-arranged to locate and confine said stack thereon, adjustable meansselectively positionable on said stack base at the rear thereof tocompensate for accumulation of the stack edge at the front,. and meansat the front of said base for adjusting said stack at the front thereofto maintain the proper level as sheets are removed therefrom and thefront edge diminishes.

12. In a sheet transfer station for moving sheets frommoves the stationin response to machine control which also provides a timed vacuum tosaid station, a substantially flat stack positioning surface adjacentsaid transfer station for holding a stack of sheets to be transferredtherefrom, means on said surface for initially compensating theaccumulated build-up at one side of said stack from any excess thicknessof one side of said sheet compared to any other side to cause said stackto be substantially level at the top thereof, other means on saidsurface compensating for the loss in build-up as said stack, diminishesfrom sheets being removed therefrom to maintain the top of said stacksubstantially level from a full stack to a partly empty stack, stationsupport means extending from said machine and base and being supportedfor movement thereon relative thereto in engagement with'said stack assaid station moves on said base to transfer sheets from the stack, aplurality of suction cups mounted for independent movement on saidstation support'means and being supported thereon above said stack toengage the top sheet thereof, each of said suction cups being retainedover said stack from downward movement freely movable by contact withthe stack top independently of the other so as to compensate for anyunevenness of the stack top.

l3. Ina sheet transfer station for moving sheets from a stack of sheetswherein the sheet station is guided and moved on a moving machine baseand a control member moves the station in response to machine controlwhich also provides a timed vacuum to said station, a substantially flatstack positioning surface adjacent said transfer station for holding astack of sheets to' be transferred therefrom, means on said surface forinitially ad-' justably lifting one side of said stack for compensatingthe accumulated build-up at one side of said stack from any excessthickness of one side of said sheet compared to any other side to causesaid stack to be substantially level at the top thereof, other means onsaid surface compensating for the loss in build-up as said stackdiminishes from sheets being removed therefrom to maintain the top ofsaid stack substantially level from a full stack to a partly emptystack, station support means extending from said machine and base andbeing supported for movement thereon relative thereto in engagement withsaid stack as said station moves on said base to transfer sheets fromthe stack, a plurality of suction cups mountedfor "independent movementon said station support means and being supported thereon above saidstack to engage 'the top sheet thereof, each of said suction cups beingretained over said stack from downward movement freely movable bycontact with the stack top independently of the other so as tocompensate for any unevenness of the stack top, and adjustable stackstop means onsaid station adjustable to determine the contact of theentire station with the stack top whereby said suction cups yieldablyengage the stack top to make suction engagement with the top sheetthereof.

14. In a sheet transfer station for moving sheets from a stack ofsheets, wherein guide members are provided on a machine base and acontrol member moves the station in response to machine control whichalso provides a timed vacuum and an independent air pressure to saidstation, a station support means extending from said guide members,means supporting said support members movably for transfer movement onsaid base guide members, a stack limiting frame mounted on said stationcomprising a pair of spaced supports mounted belowone of'said stationsupports, a pivotal shaft member mounted on and between said supports, apair of spaced block members mounted on said shaft for rotation thereon,a pair of stack engagement members mounted between said blocks onopposite sides of said shaft and being spaced different distancestherefrom, an adjustable engagement member on said stack limiting framenormally retaining said stack engagement members in set position, saidblocks being rotatable-about said shaft to select one of the positionsdiminishes.

of the stack engagement members, a sheet stack base mounted on saidmachine base below said station transfer device and, having a raisedbase bottom with a flat top surface, front, side, rear stack positioningmembers adjustably mounted on said base to be pre-arranged to locate andconfine said stack thereon, a plurality of build-up blocks selectivelypositionable on said stack base at the rear thereof to compensate foraccumulation of the stack edge at the front, and automatic compensatingplungers spring mounted on said base to compensate for stack reductionas the stack diminishes.

15. In a sheet transfer station for moving sheets from a stack ofsheets, wherein guide members are provided on a machine base and acontrol member moves the station in response to machine control whichalso provides a timed vacuum and an independent air pressure to saidstation, a pair of station support members extending from said guidemember, means supporting said support members movably for transfermovement on said base guide members, a suction lever support memberfixedly mounted on said station supports, a pair of spaced suction cuplevers mounted for pivotal movement on said suction lever supportmember, each of said levers having a position stop tab' thereon normallyresting in engagement above one of said station support members, each ofsaid levers being freely movable on its pivot upwardly and being limitedin downward "movement by said stop tabs whereby contact of said leverwith a stack will push said lever upwardly, each of saidlevers having asuction cup thereon in closed'communication with a suction line attachedthereto, a movable connecting pipe supporting each of said suction'cupsfor limited movement on said respective levers, a sheet stack basemounted on said machine base below said station transfer device andhaving a raised base bottom with'a flat top surface, front, side, rearstack positioning'members adjustably mounted on said base to bepro-arranged to locate and confine said stack thereon, a plurality ofbuild-up blocks selectively positionable on said stack base at the rearthereof to compensate for accumulation of the stack edge at the front,and automatic compensating plungers spring mounted on said base tocompensate for stack reduction as the stack 16. In a sheet transferstation for moving sheets from a stack of sheets, wherein guide membersare provided on a'rnachine base and a control member moves the stationin response to machine control which also provides a timed vacuum and anindependent air pressure to said station, a support means supportingsaid station movably for t'ransfer'movement on said base guide members,a

plurality of spaced suction cup supports mounted for pivotal movement onsaid station supports, each of said levers'being movable on its pivotupwardly and being positioned infstack contact position whereby contactof said lever with a stack will push said lever upwardly, each ofsaid'levers having a suction cup thereon in closed communication'with asuction'line attached thereto, a stack limiting frame mounted'on' saidstation, a pivotal shaft member mounted on and between said station, apair of stack engagement members mounted on'opposite sides of said shaftand being spaced different distances therefrom, an adjustable means onsaid stack limiting frame normally retaining said stack engagementmembers in'set position, a sheet'stack base mounted on said machine basebelow said station transfer device and having a raised'base' bottom witha flat top surface, front, side,

-rearstackpositioning members adjustably mounted on a stack-of sheets,wherein guide members are provided on amachinebase and a control membermoves the station in response to machine control which also provides atimed vacuum and an independent air pressure to said station, a pair ofstation support members extending from said guide member, meanssupporting said support members movably for transfer movement on saidbase guide members, a suction lever support member fixedly mounted onsaid station supports, a pair of spaced suction cup levers mounted forpivotal movement on said suction lever support member, each of saidlevers having a position stop tab thereon normally resting in engagementabove one of said station support members, each of said levers beingfreely movable on its pivot upwardly and being limited in downwardmovement by said stop tabs whereby contact of said lever with-a stackwill push said lever upwardly, each of said levers having a suction cupthereon in closed communication with a suction line attached thereto, amovable connecting pipe supporting each of said suction cups for limitedmovement on said respective levers, a stack limiting frame mounted onsaid station comprising a pair of spaced supports mounted below one ofsaid station supports, a pivotal shaft member mounted on and betweensaid supports, a pair of spaced block members mounted on said shaft forrotation thereon, a pair of stack engagement members mounted betweensaid blocks on opposite sides of said shaft and being spaced differentdistances therefrom, an adjustable engagement member on said stacklimiting frame normally retaining said stack engagement members in setposition, said blocks being rotatable about said shaft to select one ofthe positions of the stack engagement members.

18. In a sheet transfer station for moving sheets from a stack of sheetswherein guide members are provided on a machine base and a controlmember moves thestation in response to machine control which alsoprovides a timed vacuum and an independent air pressure to said station,a pair of station support members extending from said guide members,means supporting said support members movably for transfer movement onsaid base guide members, a suction lever support member fixedly mountedon said station supports, a pair of spaced suction cup levers mountedfor pivotal movement on said suction lever support member, each of saidlevers having a position stop tab thereon normally resting in engagementabove one of said station support members, each of said 10 levers beingfreely movable on its pivot upwardly and being limited in downwardmovement by said stop tabs whereby contact of said lever with a stackwill push said lever upwardly, each of said levers having a suction cupthereon in closed communication with a suction line attached thereto, amovable connecting pipe supporting each of said suction cups for limitedmovement on said respective levers, a stack limiting frame mounted onsaid station comprising a pair of spaced supports mounted below one ofsaid station supports, a pivotal shaft member mounted on and betweensaid supports, a pair of spaced block members mounted on said shaft forrotation thereon, a pair of stack engagement members mounted betweensaid blocks on opposite sides of said shaft and being spaced differentdistances therefrom, an adjustable engagement member on said stacklimiting frame normally retaining said stack engagement members in setposition, said blocks being rotatable about said shaft to select one ofthepositions of the stack engagement members, a sheet stack base mountedon said machine below said station transfer device and having a raisedbase bottom with a flat top surface, front, side and rear stackpositioning members adjustably mounted on said base to be pre-arrangedto locate and confine said stack thereon, a plurality of build-up blocksselectively positionable on 'said stack base at the rear thereof tocompensate for accumulation of the stack edge at the front, andautomatic compensating plungers spring mounted on said base tocompensate for stack reduction as the stack diminishes.

References Cited in the file of this patent UNITED STATES PATENTS Dexteret a1. July 22, 1958

